The invention relates to a safety valve as claimed in the preamble of claim 1.
Safety valves for this type are also referred to as block-bleed-block valves and employed in cleaning devices for milking installations, in particular for automatic milking of milk-providing animals, for example of cows, sheep, goats. The automatic milking procedure may be carried out by means of so-called milking robots. The safety valve is required for introducing a so-called dipping fluid onto the teat of a milk-providing animal.
Relevant national rules and guidelines, for example the American FDA guidelines, which apply to cleaning devices for milking installations and milking equipment, which come into contact with milk, have to be observed and adhered to.
The safety valve comprises two block valves and one bleed valve, and is adjusted to and fro between a first switched position which hereunder is referred to as the blocking position, and a second switched position which hereunder is referred to as the throughput position. In the blocking position, the block valves have to be simultaneously closed and the bleed valve has to be opened, wherein in the throughput position the block valves are opened and the bleed valve is closed.
Document US 2012/0017836 A1 describes a safety valve for a cleaning device for an automatic milking installation. The function and construction of a cleaning device is furthermore stated in document WO 2010/053577 A1.
By virtue of the ever increasing requirements in particular in terms of high throughput rates and of continuous operation at low maintenance or at long maintenance intervals, respectively, in the case of present cleaning devices for milking installations or milking robots, respectively, which are complex and cost-intensive, there is demand for an improved safety valve.
The solutions which have been proposed to date have an excessively large installation space, excessive costs, and low to insufficient resistance to the media used.
Against this background the object of the invention lies in providing an improved safety valve.